Insights into the Mechanism of Enhanced Rhodamine 6G Dimer Fluorescence in Mesoscopic Pluronic-Silica Matrixes

Abstract

Comparative study of the spectroscopic properties of Rhodamine 6G dimers in ethanol solutions and in mesoscopic silica-Pluronic sol−gel films has been performed by means of steady state and transient absorption and fluorescence methods. The dimers act as fluorescence quenchers in solutions, while their fluorescence yield is about 36 times higher in the mesoscopic films where they dominate in the fluorescence spectra. The difference is caused by about 6 times slower nonradiative excited state decay and about 6 times stronger oscillator strength of the fluorescence transition of the dimers in the films in comparison with solutions. We demonstrate that the dimer fluorescence originates from the oblique sandwich-type dimers both in solutions and in mesoscopic films. We suggest that the higher fluorescence yield of the dimers in the mesoscopic films is mainly caused by the stronger deviation from the planar geometrical arrangement of the sandwich-type dimer, thus causing opening of the forbidden low energy excitonic transition.

Photophysical properties of cationic dyes captured in the mesoscale channels of micron-sized metal-organic framework crystals

“…6d . Notably, no monomer emission band was observed because of possible formation of aggregates through π-π stacking interactions, which usually induces a redshifted emission 34 , 35 , 39 . Therefore, the emission properties of Rh6G@In-BTB are quite different from those of bulk crystalline Rh6G.…”

Interaction of the Fluorescent Cell-Labeling Dye Rhodamine 6G with Low-Molecular-Weight Compounds: A Comparative QCM Study of Adsorption Capacity of Rh6G for Gaseous Analytes

“…Experimental results confirm theoretical expectations. For example, in thin films, dimers are credited with making the main contribution to high-luminescence quantum yields [14]. Despite some ambiguity in the interpretation of the role of Rh6G dimers in different aggregative states, there is an undoubtable need to take into account the characteristic features of excimer aggregates (the dimers of the same compound formed in the ground state) when considering the effects with their participation.…”

Compressive imaging of transient absorption dynamics on the femtosecond timescale

“…[27] In the structured sample (black lines), in addition to the previous effects, we observe a rapid onset and decay in the TA signal due to surface traps induced on the surface of the QDs and a range of lifetimes in a variety of Rhodamine 6G agglomerates. [28,29] Fig. 2.…”